Optimal flow of high-flow nasal cannula oxygenation to prevent desaturation during sedation for bronchoscopy: a randomized controlled study.

Background: Although high-flow nasal cannula (HFNC) oxygenation is currently recommended to prevent desaturation during sedation for bronchoscopy, there is no consensus on an optimal flow rate.

Objective: To determine the optimal oxygen flow rate for HFNC to effectively prevent desaturation during sedation for bronchoscopy.

Design: Prospective, randomized, and controlled study.

Methods: Patients (n = 240) scheduled for bronchoscopy were randomized to receive HFNC with propofol sedation (fraction of inspired oxygen, 100%) at one of six flow rates of 10, 20, 30, 40, 50, and 60 L/min, designated as groups 1-6, respectively.

Results: The incidence of desaturation significantly decreased by increasing the oxygen flow rate (42.5%, 17.5%, 15%, 10%, 2.5%, and 0% for groups 1-6, respectively, p < 0.0001). The optimal oxygen flow rate for HFNC determined by probit regression to effectively prevent desaturation in 95% of patients was 43.20 (95% confidence interval, 36.43-55.96) L/min. The requirement for airway intervention was significantly decreased by increasing the oxygen flow rate.

Conclusion: An HFNC flow rate of 50-60 L/min is recommended to prevent desaturation during sedation for bronchoscopy.

Registration: NCT05298319 at ClinicalTrials.gov.